1. Field of the Invention
The present invention relates to a functional film for transfer having a functional layer comprising a compressed layer of functional fine particles on a support, an article provided with the functional layer, and a method for producing the article provided with the functional layer.
The present invention relates to a functional film for transfer having a functional layer comprising a compressed layer of functional fine particles on a support subjected to non-glare treatment, and more particularly to a functional film for transfer capable of providing a functional layer comprising a compressed layer of functional fine particles to an object article and applying non-glare treatment to the object article. Also, the present invention relates to an article provided with the functional layer and subjected to the non-glare treatment, and a method for producing the same.
In the present invention, the functional film includes both a functional film and a functional sheet. In addition, the functional film of the present invention includes a functional film in which a support is a metal.
The functional layer is a layer having a function, and the function means an action accomplished through physical and/or chemical phenomena. The functional layer includes layers having various functions, such as a conductive layer, an ultraviolet shielding layer, an infrared shielding layer, a magnetic layer, a ferromagnetic layer, a dielectric layer, a ferroelectric layer, an electrochromic layer, an electroluminescent layer, an insulating layer, a light-absorbing layer, a light selecting absorbing layer, a reflecting layer, a reflection preventing layer, a catalyst layer, a photocatalyst layer and others.
Particularly, the present invention relates to a functional film for transfer having a transparent conductive layer. In particular, the present invention relates to a functional film for transfer capable of being used for articles, represented by various displays, in which non-glare treatment is required, and more specifically to a functional film for transfer capable of providing a transparent conductive layer to an object article and applying non-glare treatment to the object article. The transparent conductive layer can be used as a transparent electrode such as an electroluminescence panel electrode, an electrochromic element electrode, a liquid crystal electrode, a transparent plane heater, or a touch panel, and can be also used as a transparent electromagnetic-wave shielding layer.
2. Disclosure of the Related Art
Hitherto, functional layers made of various functional materials are produced by the physical vapor deposition method (PVD) such as vacuum vapor deposition, laser ablation, sputtering, or ion plating, or by the chemical vapor deposition method (CVD) such as heat CVD, light CVD, or plasma CVD. These generally require a large-scale apparatus, and among these, some are not suited for forming a layer of large area.
Also, a process is known in which a layer is formed by application using the sol-gel method. The sol-gel method is suited for forming a layer of large area, but in most cases, inorganic materials must be sintered at a high temperature after the application.
For example, with respect to a transparent conductive layer, the following description can be made. At present, the transparent conductive layer is produced mainly by the sputtering method. There are various modes for the sputtering method, for example, a method of forming a layer by allowing inert gas ions, which are generated by direct current or high-frequency discharge, to be accelerated to hit the surface of a target in vacuum so as to strike out atoms constituting the target from the surface for deposition on the substrate surface.
The sputtering method is excellent in that a conductive layer having a low surface electric resistance can be formed even if it has a large area to some extent. However, it has a disadvantage that the apparatus is large, and the layer forming speed is slow. If the conductive layer is to have a still larger area from now on, the apparatus will be further enlarged. This raises a technical problem such that the controlling precision must be heightened and, from another point of view, raises a problem of increase in the production cost. Further, although the number of targets is increased to raise the speed in order to compensate for the slowness of the layer forming speed, this also is a factor that enlarges the apparatus, thereby raising a problem.
An attempt is made to produce the transparent conductive layer by the application method. In a conventional application method, a conductive paint having conductive fine particles dispersed in a binder solution is applied onto a substrate, dried, and hardened to form the conductive layer. The application method has advantages in that a conductive layer having a large area can be easily formed, that the apparatus is simple and has a high productivity, and that the conductive layer can be produced at a lower cost than by the sputtering method. In the application method, an electric path is formed by contact of the conductive fine particles with each other, whereby the electric conductivity is exhibited. However, the conductive layer produced by the conventional application method has an insufficient contact, and the obtained conductive layer has a high electric resistance value (i.e. is inferior in conductivity), thereby limiting its usage.
As the production of the transparent conductive layer by the conventional application method, Japanese Laid-open Patent Publication No. 9-109259 (1997) discloses a production method comprising the first step of applying a paint comprising conductive powders and binder resins onto a plastic film for transfer and drying it to form a conductive layer, the second step of pressing (5 to 100 kg/cm2) the conductive layer surface on a smooth surface and heating (70 to 180xc2x0 C.), and the third step of laminating this conductive layer on a plastic film or sheet and heat-press-bonding it.
In this method, a large amount of binder resins is used (100 to 500 parts by weight of conductive powders with respect to 100 parts by weight of the binder in the case of inorganic conductive powders; or 0.1 to 30 parts by weight of conductive powders with respect to 100 parts by weight of the binder in the case of organic conductive powders), so that a transparent conductive layer having a low electric resistance value cannot be obtained.
For example, Japanese Laid-open Patent Publication No. 8-199096 (1996) discloses a method in which a conductive layer forming paint comprising tin-doped indium oxide (ITO) powders, a solvent, a coupling agent and an organic or inorganic acid salt of metal, and not containing a binder is applied onto a glass plate and calcined at a temperature of 300xc2x0 C. or higher. In this method, since the binder is not used, the conductive layer has a low electric resistance value. However, since the calcining step at a temperature of 300xc2x0 C. or higher must be carried out, it is difficult to form the conductive layer on a support such as a resin film. In other words, the resin film will be melted, carbonized, or burnt by the high temperature. Although it depends on a kind of the resin film, a temperature of 130xc2x0 C. may be a limit in the case of polyethylene terephthalate (PET) film, for example.
By the application method, in the case that the support is one having flexibility such as a film, a functional layer having a large area can be easily formed. However, in the case that the support is one having poor flexibility such as a plate material, the application is difficult as compared with the case of the flexible support, and particularly it is difficult to control a layer thickness for uniformity.
Namely, in the case of the flexible film, the application can be performed by fixing a coater section and moving the film, thereby easily controlling a layer thickness. On the other hand, in the case of the plate material having poor flexibility, although the application can be performed by moving the plate material if the application area is small, accuracy of the layer thickness is liable to deteriorate due to wobbling or others by moving the plate material if the application area is large. Also, although a method moving the coater section may be mentioned, accuracy of the layer thickness deteriorates if flatness of the plate material is poor.
For forming a functional layer on a support or article having poor flexibility, a method transferring a functional layer formed on a flexible film to the support or article having poor flexibility may be considered.
For example, Japanese Laid-open Patent Publication No. 60-231396 (1985), Japanese Laid-open Patent Publication No. 60-233895 (1985) and Japanese Laid-open Patent Publication No. 2-106097 (1990) disclose forming a conductive layer on a flexible support and transferring the conductive layer from the support to a substrate having poor flexibility. However, according to these Publications, formation of the conductive layer on the flexible support is performed by the sputtering method or the vapor deposition method. The sputtering method has the problems described above and the vapor deposition method also has the same problems.
In the meantime, there are cases in which providing a functional layer to a support or an article and further applying non-glare treatment (also referred to as anti-glare treatment) to the surface thereof are required. For example, various displays represented by a Braun tube (CRT) are mentioned. In a front surface of the Braun tube, formation of a conductive layer is required in order to obtain antistatic properties and electromagnetic-wave shielding, and further, formation of a non-glare layer on the conductive layer is desired in order to reduce reflection of external light. Also, for a PDP (plasma display panel), near-infrared shielding, a color-correcting layer and the like are required in addition to the requirement of the electromagnetic-wave shielding, and a non-glare layer is also desired.
Hitherto, the non-glare treatment has been performed by, for example, a method dispersing silica particles in a binder and applying it onto a glass surface to be treated, a method spraying abrasive grains to a glass surface to be treated, or a method etching a glass surface to be treated using fluorine (for example, Japanese Laid-open Patent Publication No. 50-96128 (1975), Japanese Laid-open Patent Publication No. 55-12107 (1980) or Japanese Laid-open Patent Publication No. 59-116601 (1984)). By these methods, steps for production increase.
Japanese Laid-open Patent Publication No. 8-187997 (1996) discloses that non-glare treatment is applied to a surface of a display case using a transfer sheet. However, there is no description with regard to providing a functional layer simultaneously.
From these backgrounds, it is desired to develop a method in which a functional layer capable of exhibiting various functions, for example, a transparent conductive layer being low in electric resistance value, is obtained while utilizing the advantages of the application method that a functional layer of large area can be easily formed on a flexible support, that the apparatus is simple and has a high productivity, and that the functional layer can be produced at a low cost.
Thus, an object of the present invention is to provide a functional film for transfer, by means of the application method, having a functional layer capable of exhibiting various functions, for example, a transparent conductive layer being low in electric resistance value, to provide an article provided with the functional layer, and to provide a method for producing the article provided with the functional layer. In particular, an object of the present invention is to provide a transfer functional film for providing a functional layer with a uniform thickness to an article having poor flexibility such as a plate material, and to provide an article having poor flexibility provided with the functional layer with a uniform thickness.
An object of the present invention is to provide a functional film for transfer, by means of the application method, capable of providing a functional layer that can exhibit various functions, for example, a transparent conductive layer being low in electric resistance value, to an object article, and applying non-glare treatment to the object article, to provide an article provided with the functional layer and subjected to the non-glare treatment, and to provide a method for producing the same. In particular, an object of the present invention is to provide a transfer functional film for providing a functional layer with a uniform thickness to an article having poor flexibility such as a plate material and applying non-glare treatment to the article, and to provide an article having poor flexibility provided with the functional layer with a uniform thickness and subjected to the non-glare treatment.
Further, an object of the present invention is to provide an adhesive composition for transferring and gluing a functional layer, formed on a flexible support in a releasable state, onto an object article.
Furthermore, an object of the present invention is to provide a functional film for transfer having a functional layer comprising a compressed layer of functional fine particles and an adhesive layer composed of the adhesive composition on a support.
Conventionally, in the application method, it was considered that a functional layer cannot be formed without the use of a large amount of a binder resin, or in the case where the binder resin is not used, the functional layer cannot be obtained unless a functional substance is sintered at a high temperature.
With respect to a conductive layer, it was considered that the conductive layer cannot be formed without the use of a large amount of a binder resin, or in the case where the binder resin is not used, the conductive layer cannot be obtained unless a conductive substance is sintered at a high temperature.
Nevertheless, surprisingly as a result of eager studies made by the present inventor, it has been found out that a functional layer having mechanical strength and being capable of exhibiting various functions can be obtained by compression even without the use of a large amount of the binder resin and without calcining at a high temperature. The present inventor has found out that a transparent conductive layer having a low resistance value can be obtained with the use of a conductive material.
Further, the present inventor has found out that a functional film for transfer can be obtained by forming a functional layer on a support in a state in which the functional layer is releasable from the support, thereby arriving at the present invention.
Further, the present inventor has found out that a functional film for transfer can be obtained by forming a functional layer on a support subjected to non-glare treatment in a state in which the functional layer is releasable from the support, thereby arriving at the present invention.
The present invention is a functional film at least having a functional layer on a support, said functional layer being releasable from the support, wherein the functional layer is a compressed layer of functional fine particles. The support has flexibility.
In the present invention, as being releasable, cases shown in FIG. 1 are included.
FIG. 1(a) describes a mode of release, used in normal meaning, in which a layer A and a layer B, which contact each other, are completely released from the interface.
FIG. 1(b) and FIG. 1(c) describe modes of release in which parts of one layer A remain on another layer B although the layer A and the layer B, which contact each other, are released from the interface. Thus, in microscopic view, if each layer, after it is released, takes substantially the form of a layer, it is defined as being releasable even if it cannot be expressed as the perfect release as shown in FIG. 1(a). The present invention also includes cases in which a compressed layer of functional fine particles corresponds to the layers A of FIG. 1(b) and FIG. 1(c).
Further, in the present invention, xe2x80x9cthe functional layer being releasable from the supportxe2x80x9d means a layer in a state in which the support and the functional layer are releasable from each other. In the case that the functional film for transfer of the present invention is practically used, the support is often released from the functional layer stuck onto the object article.
The functional film for transfer of the present invention includes two types, depending on whether a surface of the functional layer is exposed or not at the time of transferring the functional layer to a transfer-object article.
First, the first type in which the surface of the functional layer is not exposed will be described below:
The present invention is the functional film, wherein a releasable layer to be released from the support is formed on the support, and the compressed layer of the functional fine particles is formed on the releasable layer, whereby the releasable layer is releasable together with the compressed layer of the functional fine particles from the support. In the case that the functional layer is transferred to a transfer-object article using the first type functional film, the functional layer is transferred to a surface of the transfer-object article so that the releasable layer exists on the functional layer.
The present invention is the functional film, wherein the releasable layer comprises a resin layer containing a resin as a main component. The resin layer is releasable together with the compressed layer of the functional fine particles from the support.
The present invention is the functional film, wherein the releasable layer comprises a hard-coating layer formed on the support and the resin layer formed on the hard-coating layer. The hard-coating layer is releasable together with the resin layer and the compressed layer of the functional fine particles from the support.
Next, the second type in which the surface of the functional layer is exposed will be described below:
The present invention is the functional film, wherein a base layer is formed on the support, and the compressed layer of the functional fine particles is formed on the base layer, whereby the compressed layer of the functional fine particles is releasable from the base layer.
The base layer is a layer not to be substantially released from the support at the time of transfer. In other words, the present invention is the functional film, wherein a layer not to be released from the support is formed on the support, and the compressed layer of the functional fine particles is formed on the layer not to be released, whereby the compressed layer of the functional fine particles is releasable from the support and the layer not to be released.
In the case that the functional layer is transferred to a transfer-object article using the second type functional film, the functional layer is transferred to a surface of the object article so that a surface of the functional layer is exposed.
The present invention is the functional film, wherein the base layer, namely, the layer not to be released, is a resin layer containing a resin as a main component.
The functional film for transfer of the present invention includes the third type capable of providing the functional layer to the object article and applying non-glare treatment to the object article at the time of transferring the functional layer to the transfer-object article.
The present invention is a transfer functional film at least having a functional layer on a support, said functional layer being releasable from the support, wherein a surface of the support at the side of the functional layer is subjected to non-glare treatment, and the functional layer is a compressed layer of functional fine particles. The support has flexibility.
The present invention is the functional film for transfer, wherein a releasable layer to be released from the support is formed on the support, and the compressed layer of the functional fine particles is formed on the releasable layer, whereby the releasable layer is releasable together with the compressed layer of the functional fine particles from the support.
The present invention is the functional film for transfer, wherein the releasable layer comprises a resin layer containing a resin as a main component. The resin layer is releasable together with the compressed layer of the functional fine particles from the support.
The present invention is the functional film for transfer, where the releasable layer comprises a hard-coating layer formed on the support and the resin layer formed on the hard-coating layer. The hard-coating layer is releasable together with the resin layer and the compressed layer of the functional fine particles from the support.
In the functional films of the first type, the second type and the third type, it is also preferable that an adhesive layer is formed on the compressed layer of the functional fine particles. In the case that the adhesive layer is not formed in the functional film, an adhesive layer may be formed on a transfer-object article in advance.
In the functional film, the compressed layer of the functional fine particles is obtained by applying a liquid in which the functional fine particles are dispersed onto the support or the resin layer (the releasable layer in the first type; the base layer, namely the layer not to be released in the second type; the releasable layer in the third type) followed by drying to form a layer containing the functional fine particles, and compressing the layer containing the functional fine particles.
In the functional film, it is preferable that the compressed layer of the functional fine particles is obtained by compressing at a compression force of at least 44 N/mm2.
At the time of producing the functional film, although the dispersion liquid of the functional fine particles may contain a small amount of a resin, it is particularly preferable that the dispersion liquid does not contain the resin. In the case that the dispersion liquid of the functional fine particles contain the resin, a content of the resin is preferably lower than 25 parts by volume with respect to 100 parts by volume of the functional fine particles.
In the functional film, in the case that conductive fine particles are used as the functional fine particles, a functional film having a conductive layer (that is, a conductive film for transfer) is obtained. In the functional film, it is also preferable that the compressed layer of the functional fine particles is a transparent conducive layer.
The present invention is an article provided with the functional layer of the functional film. In the case that the second type functional film is used, an object on which a surface of the functional layer is exposed is directly obtained. In the present invention, the functional layer may be subjected to patterning.
Further, the present invention is a method for producing an article provided with a functional layer, characterized by transferring the functional layer of the functional film from the support to the object article through an adhesive layer of the functional film and/or an adhesive layer formed on the object article to be provided with the functional layer.
The present invention is an article provided with a releasable layer comprising the functional layer of the functional film for transfer and subjected to non-glare treatment.
Furthermore, the preset invention is a method for producing an article provided with a functional layer and subjected to non-glare treatment, characterized by transferring a releasable layer comprising the functional layer of the transfer functional film from the support to an object article to be provided with the functional layer so that a surface released from the support faces outside. At the time of transfer, the adhesive layer of the functional film and/or the adhesive layer formed on the object article may be used.
According to the present invention, a functional film for transfer having a functional layer being excellent in performance is obtained by simple and convenient operations of applying and compressing. According to the present invention, an article provided with the functional layer and a method for producing the article provided with the functional layer are provided. In particular, the present invention has advantages in the case that the functional layer with a uniform thickness is provided to an article having poor flexibility such as a plate material.
According to the present invention, a transfer functional film capable of providing a functional layer having excellent performance to an object article and applying non-glare treatment to the object article is obtained by simple and convenient operations of applying and compressing. According to the present invention, an article provided with the functional layer and subjected to the non-glare treatment, and a method for producing the same are provided. In particular, the present invention has advantages in the case that the functional layer with a uniform thickness is provided to an article having poor flexibility such as a plate material and that non-glare treatment is applied to the article.
According to the present invention, an adhesive composition suitable as an adhesive for the functional film is provided. Further, a functional film having the adhesive layer composed of the adhesive composition is provided.